I really like the sound and feel of the Prophet 6! But I don't quite understand the value of the high-pass filter on this particular synth.

I understand what a high-pass filter is useful for, just not why it is included here. Based on the presets and my own limited tweaking, applying this filter makes the synth sound more digital. It reduces the fullness of the sound that I associate with analog, and that I value in analog.

Is there a unique value in a high-pass filter on an analog synth (as opposed to a digital one)? Or is its purpose simply to allow more versatile sounds (but also more similar to digital)? What do you all use the high-pass filter for and how much do you use it? I'm a beginner, and this is my first analog, so feel free to educate me.

Subtractive synthesis works by sculpting oscillator sounds. And a high pass filter besides a low pass filter means, that you can sculpt both the low frequencies and the high frequencies, to get want you want and need.

A high pass filter can be extremely useful whenever you want to reduce low frequency ranges for whatever reason, and both filters in connection allow all kinds of more nasal or narrow sound spectrums (bandpath). It's simply gorgeous that the P6 has both!

A high pass filter has nothing to do with so called "digital" sound. It's just an extremely useful and welcome tone sculpting tool on any subtractive synth!

As Jim says having a slant towards higher frequencies is not "digital sounding" it is a useful tool for sculpting the frequency range, also a High pass resonate filter can be used to boost low frequencies when the resonance is high. Try it by tuning the HP to the fundamental and boosting the resonance, set keyboard tracking to track the keyboard 100%.

I see how the high-pass filter is useful for sound sculpting. I just wonder if something else would have been more useful on an analog, like a second LFO (the Moog Sub 37 has this configuration) or different slopes for the low-pass. I have since learned that some vintage synths also included high-pass filters, so I guess there are vintage high-pass sounds that people appreciate.

Unlike the Curtis filters in the P08 and P12, the P6 lowpass filter doesn't lose the bass frequencies when you up the resonance. I never needed a high-pass filter on the P08 as a bit of resonance almost always thinned out the sound anyway. When I had a P12 I barely ever needed or used the high-pass filter. It's pretty useful on the P6.

From my own perspective, the ability to modulate the high-pass with oscillator 2 in the poly-mod section is an unexpected wonder when designing sounds. I'd argue it's the P6's secret weapon.